Role in the Center - The overall goal of the DM/BS Core is to provide a system for ensuring practical research design, high quality data management, and appropriate analyses of data. During the early planning stage of a Center project, a senior member of the core plays a critical role by providing methodological assistance focusing on research design and statistical approach. Next, core personnel provide support services in the design of data collection forms that are integrated into network-supported, menu-driven data management systems. During the analysis stage, biostatistical staff provide assistance in analysis of the research data and interpretation of statistical results. Whether core personnel provide consultation or direct assistance in the implementation of the data management and/or statistical plan depends on the needs of the project. The specific aims of the core are as follows: 1. Project Planning and Research Design a. To assist Center investigators in choosing a well focused and feasible research design during the early conceptual and planning stages of the research project. b. To assist Center investigators in increasing the efficiency of each study by balancing false positive and false negative error rates. c. To assist Center investigators in implementing multiple- study strategies that support the simultaneous exploratory and confirmatory goals typical of most research. 2. Data Management a. To assist Center investigators in the design of data collection forms to facilitate the collection of research data and transfer of this information into data management systems. b. To assist Center investigators in the design and development of secure and ergonomically-designed computerized data management systems. c. To assist Center investigators in the quality control of computerized data management systems. d. To assist Center investigators in the documentation and archiving of computerized databases and analysis programs. 3. Statistical Methods and Analysis - a. To assist Center investigators in the choice and implementation of statistical plans. b. To assist Center investigators in the statistical analysis of the research data. c. To assist Center investigators in the interpretation of the statistical results and preparation of research reports. 4. Consultation and Teaching - a. To provide a resource for initial an ongoing consultation on the general principles of research design, data management, and statistical methods. b. To educate Center investigators, research fellows, and research staff about important issues regarding research design, data management, and statistical methods.